The secondary coils inside the ignition coils are not properly routed, and therefore, they may break, if excessive stress caused by engine heat is put on the edges. Such breakage causes the output of the coil to decrease, which can result in engine malfunction. If this problem is left unattended, discharge from the broken wire may cause the plastic part of the ignition coil to melt, or the catalytic converter may be damaged from over heating.
